Is there a possibility that they might end the anime but continue the manga then start a second season?

Anything's possible, and since it looks like the novels (which both the anime and manga are based off of) just ended with the ninth volume, there's probably some material that won't be covered in the anime. In general, it seems to take about a year from the last episode for a sequel to start airing with noitaminA series, so I wouldn't expect a continuation to be announced for at least three seasons (~9 months). Even then, sequels are very rare for the noitaminA block, of which No. 6 is a part.

But I'm not particularly familiar with either the novels or manga, so this is all just speculation.

Is there a possibility that they might end the anime but continue the manga then start a second season?

Anything's possible, and since it looks like the novels (which both the anime and manga are based off of) just ended with the ninth volume, there's probably some material that won't be covered in the anime. In general, it seems to take about a year from the last episode for a sequel to start airing with noitaminA series, so I wouldn't expect a continuation to be announced for at least three seasons (~9 months). Even then, sequels are very rare for the noitaminA block, of which No. 6 is a part.

But I'm not particularly familiar with either the novels or manga, so this is all just speculation.

Is that so...Well thank you for your detailed answer. I very much appreciate it :]

I really hope it is not Tantei Opera Milky Holmes: Special Chapter
If any of the above turn out to be the final simulcast for CR Summer 2011 anime line-up it will definitely be a late simulcast(again ) Most of those anime are on their 2nd episode already.

Blade is definitely out, as all the Marvel anime were licensed by G4 before the first one aired.

In fact, Iron Man and Wolverine both premiere on July 29.

If it were the Tantei Opera Milky Holmes Special, I would not see much point in adding the box right at the time they did, as the special does not air until almost a month and a half from now.

I also suspect most people would not be happy if this were the final announcement, as many people would consider this as a ".1" announcement. This type of thing doesn't cause much of a ripple if it is fully expected (as with the second Tono to Issho series in the Spring), but even when not the last announced, is not well received even when not expected (as with the first Tono to Issho series).

To put it another way:

With the box: Announcement = "What, that's it?"

Without the box: Announcement = "Yeh! Something new!"

I also notice that Fansub Wiki lists the primary network for the special as "Tokyo MX/Nico Nico Douga". That could also mean that the English Nico Nico site would be streaming it as well.

Still practically nothing for Australia. What a surprise. I stopped pirating anime and came to Crunchyroll so long ago, spending money to support developers so I could see more anime legally. Instead I was just paying for Americans to watch it for free. My subscription runs out in September, and when it does, it will be back to pirating for me.